Uploaded image for project: 'Tapestry 5'
  1. Tapestry 5
  2. TAP5-2645

Java Time API / JSR310 Type Coercers

    XMLWordPrintableJSON

    Details

    • Type: Improvement
    • Status: Open
    • Priority: Minor
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: None
    • Labels:
      None

      Description

      Summary

      Add JSR310 / Java Time `CoercionTuple`s to Tapestry.

      Goals

      With Tapestry 5.5.0 elevating the minimum Java version to 1.8, it should provide `CoercionTuple`s for the new Java Time API ([JSR310](https://jcp.org/en/jsr/detail?id=310)):

      • Add a `CoercionTuple` for all relevant types
      • Add specific tuples to reduce possible mismatches

      Motivation

      Type coercion is deeply ingrained in Tapestry.
      And therefore it should be as mature and complete as possible for its Java version.

      The addition of the Java time API is a well thought-out replacement for the previous limited `java.util.Date`-/`java.util.Calendar`-based approach.
      By adding type coercion for the new types we could encourage developers to use them in their code, instead of working around them missing, or needing to provide their own implementation.

      Risks and Assumptions

      None to minimal risk is assumed.

      For Tapestry itself, no risk can be assumed.
      Existing type coercers won't be changed, only new ones added.

      For user projects a minimal risk of duplicate type coercers exist.
      Due to the implementation of `org.apache.tapestry5.ioc.internal.services.TypeCoercerImpl`
      user type coercers will override the newly provided ones.

      Alternatives

      Instead of automatically including the type coercers we could lock them behind a feature-flag.

      Details of Proposed Changes

      The Java Time API has well-defined `toString()` methods, so we don't need explicit `Type.class --> String.class` coercers.

      Additional type coercers are needed for type-downgrade (`LocalDateTime.class --> LocalDate.class`), due to possible parsing exception between different `String`-based output formats.

      Following type coerces will be added:

       

      * Year --> Integer
      * Integer --> Year
      
      * Month --> Integer
      * Integer --> Month
      * Month --> String (enum)
      * String --> Month (enum)
      
      * String --> YearMonth
      * YearMonth --> Year
      * YearMonth --> Month
      
      * String --> MonthDay (enum)
      * MonthDay --> Month (enum)
      
      * DayOfWeek --> Integer
      * Integer --> DayOfWeek
      * DayOfWeek --> String
      * String --> DayOfWeek
      
      * String --> LocalDate
      * LocalDate --> YearMonth
      * LocalDate --> MonthDay
      
      * LocalTime --> Long
      * Long --> LocalTime
      * String --> LocalTime
      
      * String --> LocalDateTime
      * LocalDateTime --> LocalDate
      
      * String --> OffsetDateTime
      * OffsetDateTime --> OffsetTime
      
      * String --> ZoneId
      * String --> ZoneOffset
      
      * String --> ZonedDateTime
      * ZonedDateTime --> ZoneId
      
      * Instant --> Long
      * Long --> Instant
      
      * Duration --> Long
      * Long --> Duration
      
      * String --> Period
      

      Testing

      All added functionality will be unit tested.

        Attachments

        1. TAP5-2645.diff
          16 kB
          Benjamin Weidig
        2. TAP5-2645-Documentation.md
          4 kB
          Benjamin Weidig

          Activity

            People

            • Assignee:
              Unassigned
              Reporter:
              ben-ng Benjamin Weidig
            • Votes:
              0 Vote for this issue
              Watchers:
              1 Start watching this issue

              Dates

              • Created:
                Updated: